Vacuum chamber



FIG. 1 is a view of the left side of a vacuum chamber in accordance with the present design;

FIG. 2 is a rear view thereof;

FIG. 3 is right side view thereof;

FIG. 4 is a front view thereof;

FIG. 5 is a top view thereof;

FIG. 6 is a bottom view thereof; and,

FIG. 7 is a perspective view thereof, showing the top, right side, and front of the vacuum chamber in accordance with the present design. 

CLAIM The ornamental design for a vacuum chamber, as shown and described. 